Improvement in wrenches



GEORGE c. TAFT Improvement in Wrenches.

'. iNOI 122 139 Patenit ed DJacLZE',

UNITED STATES rice.

PATENT GEORGE O. TAFT, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO JOHN H.

GOES, OF SAME PLACE.

IMPROVEMENT IN WRENCHES.

.shank, and ferrule being shown in section. Fig.

2 represents a section of the ferrule and barshank upon a somewhat larger scale. Fig. 3 represents a perspective view of the double-threaded screw-supporting thimble.

The nature of my invention con sists in the combination, with the bar and ferrule in a screwwrenoh, of a double screw-threaded binding and supporting thimble, as hereinafter described.

In the drawing, the parts marked A represent the bar of the wrench. B indicates the head; 0, the movable jaw; D, the ferrule; E, the rosette and screw; F, the Wood handle; and G, the tipnut. The ferrule D ,is provided with a screwthread formed upon its internal surface, and the shank of the bar A is provided with a screwthread formed upon its exterior. These screwthreads are of different pitch, the thread of the ferrule being somewhat finer than thatupon the bar-shank. In the present instance the ferrule is cut with a thread of sixteen to the inch and the bar with a thread of twelve to the inch; but I do not confine myself to that particular proportion, as threads of greater or less pitch can be used, according to the size and style of wrench to which they are applied. A thimble, K, is provided havin g screw-threads formed upon both its external and internal surfaces, which threads correspond in pitch to the threads on the bar and ferrule, respectively. v

When the parts of the wrench are put together the ferrule D is adjusted at the position shown in Fig. 2, its upper end being set at a short distance below the shoulder a. The thimble K is then turned onto the bar A, and when it reaches the lower end of the ferrule D its external thread engages with the thread on the interior of the ferrule, and with its further forward motion runs up into the interior of the ferrule, while, at the same time, owing to the difference of pitch between fhe inner and outer threads, the'ferrule D is moved up the bar until it strikes the shoulder a, which stops its further progress and causes the thimble K to bind firmly in between the ferrule and bar at the position indicated in Fig. 1. The ferrule D is thus forced firmly up against the shoulder a and there securely held, the parts being as rigidly connected as though the bar and ferrule .were cast in a single piece, while, at the same time, the ferrule is, by the thimble K, sup-- ported so that it cannot be crushed in by any lateral pressure or a blow upon its side. This permits of the lower part of the ferrule being made very light and thin. A small rim of the lower end of the ferrule extends below the thimble K, when the latter is set up to place, for supporting the upper end of the wood handle, which latter is held in place by the tip-nut G in the ordinary manner.

It will be observed that the thimble K must be started into the ferrule before the latter is moved up against the shoulder a; otherwise the thimble cannot be run up into the interior of'the ferrule, as the parts bind as soon as the ferrule and shoulders are brought together.

Having described my improvements in screwwrenches, what I claim therein as new and of my invention, and desire to secure by Letters Patcut, is-

The combination, with the bar A and ferrule D, of the thimble K, having internal and external screw-threads of different pitch, substantially as and for the purpose set forth.

' GEO. G. TAFT.

Witnesssz' UHAS. H. BURLEIGH', A; E. PEIRGE. (100) 

